KR102287923B1 - Polishing pad, preparation method thereof, and preparation method of semiconductor device using same - Google Patents

Abstract

The polishing pad according to the embodiment controls the bonding force between the abrasive particles and the polishing pad by controlling the content of elements present in the polishing layer, in particular, the oxygen (O) element, and the total content of oxygen (O) and nitrogen (N) elements. and thereby improving the bonding force between the abrasive particles and the semiconductor substrate (wafer), thereby improving the polishing rate. Therefore, it is possible to efficiently manufacture a high-quality semiconductor device using the polishing pad.

Description

Polishing pad, manufacturing method thereof, and manufacturing method of a semiconductor device using the same

Embodiments relate to a polishing pad that can be used in a chemical mechanical planarization (CMP) process of a semiconductor, a method of manufacturing the same, and a method of manufacturing a semiconductor device using the same.

In the chemical mechanical polishing (CMP) process of the semiconductor manufacturing process, a semiconductor substrate such as a wafer is attached to a head and brought into contact with the surface of a polishing pad formed on a platen, and a slurry is supplied to chemically clean the semiconductor substrate surface. It is a process of mechanically planarizing the concavo-convex part of the surface of a semiconductor substrate by moving the surface plate and the head relative to each other while reacting with the

The polishing pad is an essential raw material that plays an important role in the CMP process, and is generally made of a polyurethane resin, and the polyurethane resin is a urethane-based prepolymer obtained by reacting a diisocyanate compound with a polyol, a curing agent, a foaming agent, etc. include

Of these, the urethane-based prepolymer may have different properties and properties depending on the type and content of the diisocyanate compound and polyol used during polymerization, and these properties may greatly affect the performance of the CMP process. Therefore, controlling not only the physical properties of the polishing pad but also the physical properties of the prepolymer is an important factor that can significantly change the properties of the CMP pad.

In addition, since the polishing layer of the polishing pad manufactured with the above components directly interacts with the surface of the semiconductor substrate during the CMP process, it affects the processing quality of the surface of the semiconductor substrate. The polishing rate can be sensitively changed.

Therefore, in order to improve the polishing rate of the CMP process, there is an urgent need to develop a polishing pad capable of designing an optimum range of physical properties and polishing rate conditions by controlling the components and physical properties of the polishing layer.

Korean Patent Publication No. 2016-0027075

According to the present invention, as a result of continuous research, recognizing that the type and content of components used in manufacturing a polishing pad affect the processing quality of the surface of the semiconductor substrate and the polishing rate can be sensitively changed, each It was found that the bonding force between the polishing pad and the abrasive particles, and further, the bonding strength between the abrasive particles and the semiconductor substrate, varies depending on the content of the element, which affects the CMP performance such as the polishing rate.

Accordingly, an object of the embodiment is to control the content of element oxygen (O) in the polishing layer, and the total content of nitrogen (N) and oxygen (O) elements to significantly improve the polishing rate, a polishing pad, a method for manufacturing the same, and a method of manufacturing a semiconductor device using the polishing pad.

According to one embodiment, an abrasive layer comprising a cured product of a composition including a urethane-based prepolymer, a curing agent and a foaming agent, wherein the content of oxygen (O) element in the abrasive layer is 15 based on the total weight of the abrasive layer and 19 wt% to 19 wt%, wherein the total content of nitrogen (N) and oxygen (O) elements in the abrasive layer is 20 wt% to 27 wt% based on the total weight of the abrasive layer.

According to another embodiment, preparing a composition by sequentially or simultaneously mixing a urethane-based prepolymer, a curing agent, and a foaming agent; and injecting the composition into a mold and curing it to form an abrasive layer, wherein the content of element oxygen (O) in the abrasive layer is 15 wt% to 19 wt% based on the total weight of the abrasive layer, There is provided a method of manufacturing a polishing pad, wherein the total content of nitrogen (N) and oxygen (O) in the polishing layer is 20 wt % to 27 wt % based on the total weight of the polishing layer.

According to another embodiment, comprising the step of polishing the surface of the semiconductor substrate using a polishing pad, wherein the polishing pad comprises a polishing layer comprising a cured product of a composition including a urethane-based prepolymer, a curing agent and a foaming agent, , the content of oxygen (O) element in the abrasive layer is 15 wt% to 19 wt% based on the total weight of the abrasive layer, and the total content of nitrogen (N) and oxygen (O) in the abrasive layer is A method of manufacturing a semiconductor device is provided in an amount of 20 wt% to 27 wt% based on the total weight.

In the polishing pad according to the embodiment, by controlling the content of elements present in the polishing layer, particularly the content of oxygen (O) element, and the total content of oxygen (O) and nitrogen (N) elements, the abrasive particles and the polishing pad By controlling the bonding force, thereby improving the bonding strength between the abrasive particles and the semiconductor substrate (wafer), it is possible to improve the polishing rate.

Furthermore, a high-quality semiconductor device can be efficiently manufactured using the polishing pad.

1 shows the polishing rates of the polishing pads prepared in Examples 1 to 4 and Comparative Examples 1 to 3;
2 is a schematic flowchart of a semiconductor device manufacturing process according to an exemplary embodiment.

In the following description of embodiments, "above" and "under" each layer, pad or sheet, etc., when described as being formed on or under each layer, pad or sheet, etc. includes all those formed directly or indirectly through other components.

The criteria for the upper/lower of each component will be described with reference to the drawings. The size of each component in the drawings may be exaggerated for explanation, and does not mean a size actually applied.

In the present specification, "including" a component means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in the present specification are modified by the term "about" in all cases unless otherwise specified.

[polishing pad]

The polishing pad according to an embodiment includes a polishing layer including a cured product of a composition including a urethane-based prepolymer, a curing agent, and a foaming agent, and the content of oxygen (O) element in the polishing layer is the total weight of the polishing layer. 15 wt% to 19 wt%, and the total content of nitrogen (N) and oxygen (O) elements in the abrasive layer is 20 wt% to 27 wt% based on the total weight of the abrasive layer.

According to one embodiment of the present invention, the polishing rate can be significantly improved according to the content of the oxygen (O) element and the total content of nitrogen (N) and oxygen (O) elements in the polishing layer.

First, the content of oxygen (O) element in the polishing layer may affect the bonding force between the polishing pad and the abrasive particles and the bonding strength between the abrasive particles and the semiconductor substrate. Therefore, by controlling the content of the oxygen (O) element in the polishing layer, the bonding force thereof can be adjusted, thereby improving the polishing rate.

The content of element oxygen (O) in the abrasive layer may be 15 wt% to 19 wt%, 16 wt% to 18.9 wt%, 15 wt% to 18 wt%, or 16 wt% to 18 wt% based on the total weight of the abrasive layer. % by weight. Specifically, when the content of the oxygen (O) element is within the above range, the abrasive particles used during polishing, for example, ceria (CeO ₂ ), the bonding force between the particles and the polishing pad is appropriately controlled, and thus the ceria (CeO _{2 )} ), the bonding force between the particles and the semiconductor substrate (wafer) is improved, thereby improving the polishing rate. When the content of the oxygen (O) element exceeds 19% by weight, _{the bonding strength between the ceria (CeO 2} ) particles and the polishing pad used during polishing is excessively increased, thereby reducing the bonding strength between _{the ceria (CeO 2 ) particles and the wafer.} Therefore, it may adversely affect the polishing rate. On the other hand, when the content of the oxygen (O) element is less than 15% by weight _{, the adhesion between the polishing pad and the ceria (CeO 2} ) particles is lowered, so the bonding with the wafer is rather increased, and thus defects and scratches are increased. there may be

In addition, the total content of nitrogen (N) and oxygen (O) elements in the abrasive layer is 20 wt% to 27 wt%, 22 wt% to 27 wt%, 23 wt% to 27 wt% based on the total weight of the abrasive layer %, or 22% to 25% by weight. Since the total content of nitrogen (N) and oxygen (O) elements in the polishing layer affects the bonding strength with the semiconductor substrate or the slurry, the polishing rate may be improved when the above ranges are satisfied. If the total content of nitrogen (N) and oxygen (O) elements in the polishing layer is less than 20% by weight, defects and scratches may increase, and if it exceeds 27% by weight, the polishing rate is lowered there may be

Meanwhile, the main elements in the polishing layer may include carbon (C), nitrogen (N), oxygen (O), and hydrogen (H) elements. In addition, the main elements in the polishing layer may include carbon (C), nitrogen (N), oxygen (O), hydrogen (H), Si (silicon) and chlorine (Cl) elements. The total content of major elements in the polishing layer, for example, the total content of carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) elements, is 92 wt % to 96 wt % based on the total weight of the polishing layer. % by weight, 92% to 95.5% by weight, 92% to 94% by weight, or 94% to 96% by weight.

The total content of other elements other than the main elements in the polishing layer, for example, carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) elements, based on the total weight of the polishing layer, 4 wt% to 8 wt%, 4.5 wt% to 8 wt%, 5 wt% to 7 wt%, 4 wt% to 7 wt%, or 6 wt% to 8 wt%.

In addition, the total content of nitrogen (N), oxygen (O) and hydrogen (H) elements in the abrasive layer is based on the total content of major elements in the abrasive layer, specifically, carbon (C), nitrogen in the abrasive layer 30 wt% to 35 wt%, 32 wt% to 35 wt%, or 33 wt% to 34 wt% based on the total content of (N), oxygen (O) and hydrogen (H) elements. Since the total content of nitrogen (N), oxygen (O), and hydrogen (H) elements in the polishing layer affects the bonding strength with the semiconductor substrate or the slurry, the polishing rate can be further improved when the above ranges are satisfied.

The content of each element in the polishing layer may be measured by nuclear magnetic resonance (NMR) or element analysis (EA), and the content of each element in the polishing layer is determined by applying an element to the top pad of the polishing pad. Measurements were made using an analyzer, model name Flash2000 (Thermo Fisher Scientific, Germany).

According to one embodiment of the present invention, the oxygen (O) element in the polishing layer may be derived from the diisocyanate compound and polyol used in the urethane-based prepolymer. In addition, the oxygen (O) element in the polishing layer may be derived from a curing agent.

Urethane-based prepolymer

The urethane-based prepolymer may be an important factor in controlling oxygen (O) element, hydrogen (H) element and nitrogen (N) element, and their total content. That is, the content of the oxygen (O) element in the polishing layer may vary depending on the type of the diisocyanate compound and the polyol used in polymerization of the urethane-based prepolymer, and the content thereof. In addition, each content of oxygen (O) element, hydrogen (H) element and nitrogen (N) element in the polishing layer according to the type of diisocyanate compound and polyol used during polymerization of the urethane-based prepolymer, and their content, and their total content may vary.

Specifically, the urethane-based prepolymer may include a prepolymerization reaction product of at least one diisocyanate compound and at least two polyols, and the oxygen (O) element in the polishing layer is derived from the diisocyanate compound and the polyol. it could be

The prepolymerization reaction generally refers to a reaction in which a polymer having a relatively low molecular weight is obtained by stopping polymerization of a monomer in an intermediate stage to facilitate molding in the production of a final polymer molded article. Thus, the prepolymer comprising the prepolymerization reaction product can be formed into a final product by itself or by further reaction with another polymerizable compound or curing agent. For example, the weight average molecular weight (Mw) of the urethane-based prepolymer may be 500 g/mol to 3,000 g/mol, 600 g/mol to 2,000 g/mol, or 700 g/mol to 1,500 g/mol.

The at least one diisocyanate compound may be at least one aromatic diisocyanate compound and/or at least one aliphatic diisocyanate compound, for example, toluene diisocyanate (TDI), naphthalene-1,5-di Isocyanate (naphthalene-1,5-diisocyanate), para-phenylene diisocyanate (p-phenylene diisocyanate), tolidine diisocyanate, diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate ( It may include at least one selected from the group consisting of hexamethylene diisocyanate, HDI), dicyclohexylmethane diisocyanate (H12MDI), and isophorone diisocyanate. Specifically, the diisocyanate compound is toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (hexamethylene diisocyanate, HDI), and dicyclohexylmethane diisocyanate (dicyclohexylmethane) diisocyanate, H12MDI) may be at least one selected from the group consisting of.

Meanwhile, the polyol refers to a compound having two or more hydroxyl groups, and the two or more polyols may be one or more monomolecular polyols and one or more polymer polyols.

By controlling the type and content of the monomolecular polyol and the polymer polyol, the content of each element in the polishing layer, specifically, the content of element oxygen (O) can be controlled, and physical properties including gel time and hardness can be changed. can do it In addition, even if the content of oxygen (O) element in the polishing layer is controlled by using only one kind of the polyol, the physical properties, particularly hardness, of the polishing pad may be adversely affected.

The monomolecular polyol may have a weight average molecular weight of 70 to 200 g/mol, and the high molecular weight polyol may have a weight average molecular weight of 300 g/mol to 3,000 g/mol.

The monomolecular polyol may include at least one selected from the group consisting of ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), propanediol (PDO) and methylpropanediol (MP-diol). Specifically, in consideration of the gel time and hardness, the monomolecular polyol may include diethylene glycol (DEG), propylene glycol (PG), or a mixture thereof.

The polymeric polyol is polytetramethylene glycol (PTMG), polytetramethylene etherglycol (PTMEG), polyether polyol, polyester polyol, polycarbonate polyol ) and polycaprolactone polyol (polycarprolactone polyol). It may be at least one selected from the group consisting of tetramethylene ether glycol (PTMEG).

The molar ratio of the oxygen (O) element derived from the polyol and the oxygen (O) element derived from the diisocyanate compound may be 1:0.1 to 0.5, specifically 1:0.1 to 0.4.

The mixing weight ratio of the diisocyanate compound and the polyol may be 1:1.35 to 1.55 weight ratio, specifically 1:1.35 to 1.53 weight ratio, and more specifically 1:1.40 to 1.50 weight ratio.

A mixing weight ratio of the monomolecular polyol and the polymer polyol may be 1: 8 to 10, specifically 1: 8.5 to 9.8, and more specifically 1: 8.5 to 9.6. When the mixing weight ratio of the monomolecular polyol and the polymer polyol is within the above range, the hardness desired in the present invention may be realized. If the mixing weight ratio is out of the above range, hardness may be excessively increased or decreased excessively.

In addition, the mixing weight ratio of the diisocyanate compound and the polymer-type polyol may be 1: 1.2 to 1.43, specifically 1: 1.25 to 1.43, and more specifically 1: 1.25 to 1.35.

On the other hand, the mixing weight ratio of the diisocyanate compound and the monomolecular polyol may be 1: 0.11 to 0.15, specifically 1: 0.12 to 0.14, more specifically 1: 0.13 to 0.14.

According to an embodiment of the present invention, the polishing pad may have a mixing weight ratio of the diisocyanate compound and the polyol of 1: 1.35 to 1.55; A mixing weight ratio of the monomolecular polyol and the high molecular polyol 1: 8 to 10; A mixing weight ratio of the diisocyanate compound and the polymer-type polyol 1: 1.2 to 1.43; and a mixing weight ratio of the diisocyanate compound and the monomolecular polyol 1: 0.11 to 0.15;

The content of the diisocyanate compound may be 29.9 wt% to 35 wt% based on the total weight of the composition (composition for manufacturing a polishing pad). Specifically, the content of the diisocyanate compound may be 30 wt% to 34 wt%, 30 wt% to 33 wt%, 32 wt% to 34 wt%, or 31 wt% to 33 wt% based on the total weight of the composition there is. When the content of the diisocyanate compound exceeds the above range, the total content of nitrogen (N) and oxygen (O) elements in the abrasive layer becomes excessively large, which may adversely affect the polishing rate. Since the total content of nitrogen (N) and oxygen (O) elements becomes too small, defects and scratches may increase.

The total content of the two or more polyols may be 42 wt% to 47 wt%, specifically 44 wt% to 47 wt%, based on the total weight of the composition (composition for manufacturing a polishing pad).

The content of the polymer-type polyol is 35 wt% to 42.8 wt%, 38 wt% to 42 wt%, 39 wt% to 42 wt%, or 40 wt% to 42 wt% based on the total weight of the composition (composition for manufacturing a polishing pad) % by weight. When the content of the polymer-type polyol is less than the above range, the content of element oxygen (O) in the polishing layer may be reduced, which may adversely affect the polishing rate and the number of defects.

The content of the monomolecular polyol is 4.0 wt% to 4.5 wt%, specifically 4.1 wt% to 4.5 wt%, more specifically 4.2 wt% to 4.4 wt%, based on the total weight of the composition (composition for manufacturing a polishing pad) It can be %. When the content of the monomolecular polyol is less than the above range, the content of element oxygen (O) in the polishing layer may be reduced, which may adversely affect the polishing rate and the number of defects.

The urethane-based prepolymer may have a diisocyanate compound end group in an amount of 8 wt% to 12 wt%. Specifically, the urethane-based prepolymer may have an end group of the diisocyanate compound in an amount of 8 wt% to 10 wt%.

Method for preparing urethane-based prepolymer

The urethane-based prepolymer may be prepared by prepolymerizing one or more diisocyanate compounds and two or more polyols as described above.

In this process, by controlling the type and content of each diisocyanate compound and polyol input, the content of each element in the abrasive layer, specifically, the content of each element of oxygen (O), hydrogen (H) and nitrogen (N); Or their total content can be controlled.

The content of each type of diisocyanate compound in the urethane-based prepolymer and the degree of reaction or unreacted can be measured using NMR equipment. can be manufactured.

In addition, an additional diisocyanate compound or monomer such as alcohol, or other additives may be further added to the prepolymerization reaction.

hardener

The curing agent may be an important factor in controlling the content of the oxygen (O) element and/or the nitrogen (N) element content. That is, the content of the oxygen (O) element and/or the content of the nitrogen (N) element in the polishing layer may vary according to the type and content of the curing agent. For example, when an alcohol-based amine curing agent is used, the content of element oxygen (O) may vary, and when a curing agent containing nitrogen (N) is used, the content of element nitrogen (N) may vary.

The curing agent may include a nitrogen (N)-containing curing agent, for example, 4,4'-methylenebis(2-chloroaniline) (4,4'-methylenebis(2-chloroaniline); MOCA), diethyl toluenediamine (diethyltoluenediamine; DETDA), diaminodiphenylmethane, diaminodiphenylsulfone, m-xylylenediamine, isophoronediamine, ethylenediamine, Diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine and bis(4-amino-3-chlorophenyl)methane (bis(4-amino- 3-chlorophenyl) methane) may include one or more selected from the group consisting of. Specifically, the curing agent may include 4,4'-methylenebis(2-chloroaniline) (4,4'-methylenebis(2-chloroaniline); MOCA).

The content of the curing agent may be an important factor in improving the physical properties and polishing rate of the polishing pad of the present invention.

For example, the content of the curing agent may be 16.0 wt% to 20 wt%, 17.0 wt% to 19.3 wt%, 17.0 wt% to 19.0 wt%, or 18.0 wt% to 19.3 wt% based on the total weight of the composition there is. When the curing agent in the above range is included, physical properties such as hardness, tensile strength, elongation and modulus of the polishing pad can be improved. In addition, when the content of the curing agent is too small, the content of oxygen (O) and nitrogen (N) elements in the polishing layer may deviate from the scope of the present invention.

On the other hand, the diisocyanate compound and the curing agent of the urethane-based prepolymer, based on the number of moles of reactive groups in each molecule, in a molar equivalent ratio of 1:0.8 to 1:1.2, or 1:0.9 to 1:1.1 They may be mixed in a molar equivalent ratio. Here, "based on the number of moles of each reactive group" means, for example, based on the number of moles of diisocyanate compound groups of the urethane-based prepolymer and the number of moles of reactive groups (amine groups) of the curing agent. Accordingly, the molar equivalent ratio of the diisocyanate compound terminal group of the urethane-based prepolymer and the amine group of the curing agent may be 1:0.8 to 1.2. The urethane-based prepolymer and the curing agent may be added at a constant rate during the mixing process by controlling the feeding rate to be added per unit time in amounts satisfying the molar equivalent ratio exemplified above.

blowing agent

The foaming agent is not particularly limited as long as it is commonly used to form pores of the polishing pad.

For example, the foaming agent may be at least one selected from a solid foaming agent having a hollow structure, a liquid foaming agent using a volatile liquid, and an inert gas.

The solid foaming agent may be thermally expanded microcapsules, which may be obtained by heating and expanding thermally expandable microcapsules. The thermally expanded microcapsule is a structure of an already expanded microballoon, and has the advantage of uniformly controlling the particle size of the pores by having a uniform particle size. Specifically, the solid foaming agent may be a micro-balloon structure having an average particle diameter of 5 μm to 200 μm.

The thermally expandable microcapsules may include: a shell including a thermoplastic resin; And it may include a foaming agent encapsulated inside the shell. The thermoplastic resin may be at least one selected from the group consisting of a vinylidene chloride-based copolymer, an acrylonitrile-based copolymer, a methacrylonitrile-based copolymer, and an acrylic copolymer. Further, the blowing agent may be at least one selected from the group consisting of hydrocarbons having 1 to 7 carbon atoms.

The solid foaming agent may be used in an amount of 0.1 wt% to 2.0 wt% based on the total weight of the composition. Specifically, the solid foaming agent may be used in an amount of 0.5 wt% to 1.5 wt%, or 0.8 wt% to 1.4 wt%, based on the total weight of the composition.

The type of the inert gas is not particularly limited as long as it does not participate in the reaction between the urethane-based prepolymer and the epoxy curing agent. For example, the inert gas may be at least one selected from the group consisting of nitrogen (N) gas (N ₂ ), carbon dioxide gas (CO ₂ ), argon gas (Ar), and helium gas (He). Specifically, the inert gas may be a nitrogen (N) gas (N ₂ ) or a carbon dioxide gas (CO ₂ ).

The inert gas may be introduced in a volume corresponding to 10% to 30% of the total volume of the composition. Specifically, the inert gas may be introduced in a volume corresponding to 15% to 30% of the total volume of the composition.

Surfactants

According to one embodiment of the present invention, the composition may further include a surfactant.

The surfactant may serve to prevent overlapping and convergence of the formed pores. Specifically, the surfactant is a silicone-based nonionic surfactant, but may be variously selected according to the physical properties required for the polishing pad.

As the silicone-based nonionic surfactant, a silicone-based nonionic surfactant having a hydroxyl group may be used alone or may be used together with a silicone-based nonionic surfactant having no hydroxyl group.

The silicone-based nonionic surfactant having a hydroxyl group is not particularly limited as long as it has excellent compatibility with an isocyanate-containing compound and an active hydrogen compound and is widely used in the polyurethane technology field. A commercially available material of the silicone-based nonionic surfactant having a hydroxyl group is, for example, Dow Corning's DOW CORNING 193 (silicone glycol copolymer, liquid; specific gravity at 25°C: 1.07; viscosity at 20°C: 465 mm/s ; flash point: 92 ℃) (hereinafter referred to as DC-193) and the like.

The commercially available silicone nonionic surfactant having no hydroxyl group is, for example, Dow Corning's DOW CORNING 190 (silicone glycol copolymer, Gardner color number: 2; specific gravity at 25°C: 1.037; viscosity at 25°C: 2000 ㎟/s; Flash point: 63 ℃ or higher; Inverse solubility point (1.0 % water solution): 36 ℃) (hereinafter referred to as DC-190), etc.

The surfactant may be included in an amount of 0.1 to 2% by weight based on the total weight of the composition. Specifically, the surfactant is 0.2 to 1.8 wt%, 0.2 to 1.5 wt%, 0.2 to 1.6 wt%, 0.1 to 0.5 wt%, 0.2 to 0.7 wt%, or 0.2 to 1.0 wt%, based on the total weight of the composition may be included in the amount of When the surfactant is included in an amount within the above range, pores derived from the gaseous foaming agent may be stably formed and maintained in the mold.

other additive compounds

According to one embodiment of the present invention, in addition to the above-described materials in the composition, other additive compounds may be further included. As the other additive compounds, various other additive compounds commonly used may be added as long as they do not adversely affect the purpose of the present invention.

The other additive compound is 0.2 wt% to 4.0 wt%, 0.5 wt% to 3.8 wt%, 0.8 wt% to 3.5 wt%, 1.0 wt% to 3.5 wt%, 0.8 wt% to 2.5 wt%, based on the total weight of the composition %, or 2.5% to 3.5% by weight.

For example, as the other additive compound, one selected from the group consisting of a reaction rate regulator, a chain extender, a catalyst, an additional curing agent other than the curing agent, and combinations thereof may be included.

According to one embodiment of the present invention, based on the total weight of the composition, the content of the diisocyanate compound is 30% to 34% by weight, the content of the polymeric polyol is 38% to 42% by weight, and the The content of the monomolecular polyol may be 4.1 wt% to 4.5 wt%.

According to one embodiment of the present invention, based on the total weight of the composition, the content of the diisocyanate compound is 30% to 34% by weight, the content of the polymeric polyol is 38% to 42% by weight, and the The content of the monomolecular polyol may be 4.1 wt% to 4.5 wt%, and the content of the curing agent may be 17.0 wt% to 19.3 wt%. When the content of the components satisfies the above range, the total content of oxygen (O) element and nitrogen (N) and oxygen (O) elements in the polishing layer desired in the present invention may be realized.

[Manufacturing method of abrasive pad]

A method of manufacturing a polishing pad according to an embodiment includes: preparing a composition by sequentially or simultaneously mixing a urethane-based prepolymer, a curing agent, and a foaming agent; and injecting the composition into a mold and curing it to form an abrasive layer, wherein the content of element oxygen (O) in the abrasive layer is 15 wt% to 19 wt% based on the total weight of the abrasive layer, The total content of nitrogen (N) and oxygen (O) in the abrasive layer may be 20 wt% to 27 wt% based on the total weight of the abrasive layer.

According to one embodiment of the present invention, in the method of manufacturing the polishing pad, the content, type, ratio, etc. of each component are the same as those described above with respect to the polishing pad.

In addition, the step of preparing the composition (raw composition) comprises the steps of preparing a first composition comprising a urethane-based prepolymer; Preparing a second composition comprising a curing agent; preparing a third composition comprising a blowing agent; and sequentially or simultaneously mixing the first composition with the second composition and the third composition to prepare a raw material composition.

In addition, if necessary, a surfactant may be further added to the composition. The type and content of the surfactant are as described above.

In addition, at least one foaming agent selected from a liquid foaming agent using a volatile liquid and a gaseous foaming agent such as an inert gas may be further mixed when preparing the composition, if necessary.

The mixing may be performed by mixing the first composition with the second composition and then further mixing the third composition, or mixing the first composition with the third composition and further mixing the second composition. can

As an example, the urethane-based prepolymer, the curing agent, and the foaming agent may be added to the mixing process at substantially the same time. there is.

As another example, the urethane-based prepolymer, the foaming agent, and the surfactant may be mixed in advance, and then the curing agent may be added, or the curing agent and the inert gas may be added together.

The mixing may be performed at a speed of 1,000 to 10,000 rpm, or 4,000 to 7,000 rpm. In the above speed range, it may be more advantageous for the inert gas and the blowing agent to be evenly dispersed in the composition.

In addition, the step of preparing the composition may be performed at 50 °C to 150 °C conditions, and, if necessary, may be performed under vacuum defoaming conditions.

The step of injecting and curing the composition into a mold to form a polishing layer may be performed under a ^{temperature condition of 60° C. to 120° C. and a pressure condition of 50 kg/m 2} to 200 kg/m ^{2 .}

In addition, the manufacturing method may further include a process of cutting the surface of the obtained polishing pad, a process of processing a groove on the surface, an adhesion process with a lower layer, an inspection process, a packaging process, and the like. These processes may be performed in the manner of a conventional polishing pad manufacturing method.

[Physical properties of abrasive pad]

The polishing pad according to the embodiment of the present invention can improve physical properties and polishing rate.

Specifically, the thickness of the polishing layer may be 0.8 mm to 5.0 mm, 1.0 mm to 4.0 mm, 1.0 mm to 3.0 mm, 1.5 mm to 2.5 mm, 1.7 mm to 2.3 mm, or 2.0 mm to 2.1 mm. When it is within the above range, it is possible to sufficiently exhibit basic physical properties as an abrasive layer while minimizing the deviation of the particle size for each upper and lower part of the pores.

The specific gravity of the polishing layer may be 0.6 g/cm 3 to 0.9 g/cm 3 , or 0.7 g/cm 3 to 0.85 g/cm 3 .

The hardness of the polishing layer may be 45 Shore D to 80 Shore D, 45 Shore D to 70 Shore D, 45 Shore D to 60 Shore D, 50 Shore D to 60 Shore D, or 55 Shore D to 60 Shore D.

The tensile strength of the polishing layer is 16 N/mm ² to 25 N/mm ² , 18 N/mm ² to 25 N/mm ² , 20 N/mm ² to 25 N/mm ² , or 20 N/mm ² to 24 N/mm ² .

The elongation of the polishing layer may be 95% to 200%, 98% to 200%, 100% to 150%, or 100% to 120%.

The modulus of the polishing layer is 50 kgf/cm ² to 130 kgf/cm ² , 50 kgf/cm ² to 125 kgf/cm ² , 55 kgf/cm ² to 125 kgf/cm ² or 60 kgf/cm ² to 120 kgf It can be /cm ^{2 .}

In addition, the polishing pad includes micropores.

The micropores may be included in 100 to 300, 150 to 300, or 100 to 250 per ^{0.3 cm 2} area of the polishing layer.

The number average diameter of the micropores may be 10 μm to 50 μm, 20 μm to 50 μm, 20 μm to 40 μm, 20 μm to 30 μm, or 30 μm to 50 μm. As a specific example, the micropores may have a number average diameter of 20 μm to 25 μm.

In addition, the total area of the micropores may be 30% to 60%, 35% to 50%, or 40% to 50% based on the total area of the polishing layer.

In addition, the micropores may be included in an amount of 30% to 70% by volume, 30% to 70% by volume, or 40% to 60% by volume based on the total volume of the polishing layer.

The polishing layer may have a groove on its surface for mechanical polishing. The groove may have an appropriate depth, width and spacing for mechanical polishing, and is not particularly limited.

The polishing pad may further include a support layer stacked with the polishing layer. The support layer serves to absorb and disperse an impact applied to the abrasive layer while supporting the abrasive layer. The support layer may include a nonwoven fabric or suede, and may have a thickness of 0.5 mm to 1 mm and a hardness of 60 Asker C to 90 Asker C.

In addition, an adhesive layer may be inserted between the polishing layer and the support layer. The adhesive layer may include a hot melt adhesive. The hot melt adhesive may be at least one selected from the group consisting of a polyurethane resin, a polyester resin, an ethylene-vinyl acetate resin, a polyamide resin, and a polyolefin resin. Specifically, the hot melt adhesive may be at least one selected from the group consisting of a polyurethane resin and a polyester resin.

The removal rate of the polishing pad, for example, the oxide (O) film polishing rate using the ceria slurry is 3000 Å/min to 4000 Å/min, 3200 Å/min to 4000 Å/min, 3500 Å/min to 4000 Å/min, or from 3700 Å/min to 4000 Å/min. The polishing rate may be an initial polishing rate immediately after the polishing pad is manufactured (ie, immediately after curing).

In addition, the pad cut rate of the polishing pad is 15 μm/hr to 45 μm/hr, 20 μm/hr to 35 μm/hr, 25 μm/hr to 45 μm/hr, 25 μm/hr to 35 μm/hr.

According to one embodiment of the present invention, the content of oxygen (O) element in the polishing layer is 15 wt% to 19 wt% based on the total weight of the polishing layer, and the total amount of nitrogen (N) and oxygen (O) elements is When the content is 20 wt% to 27 wt% based on the total weight of the polishing layer, _{the bonding strength of the abrasive particles, for example, ceria (CeO 2} ) particles and the polishing pad, becomes appropriate, and thus the ceria particles and the semiconductor substrate The bonding force of the (wafer) is improved, so that the polishing rate can be improved.

[Method for manufacturing semiconductor device]

A method of manufacturing a semiconductor device according to an embodiment includes polishing a surface of a semiconductor substrate using the polishing pad according to the embodiment.

That is, the method of manufacturing a semiconductor device according to an embodiment includes polishing the surface of a semiconductor substrate using a polishing pad, wherein the polishing pad is a cured product of a composition including a urethane-based prepolymer, a curing agent and a foaming agent. and an abrasive layer containing The total content of may be 20 wt% to 27 wt% based on the total weight of the abrasive layer.

The method of manufacturing the semiconductor device includes: mounting a polishing pad including a polishing layer on a surface plate; and polishing the surface of the wafer by rotating the polishing surface of the polishing layer relative to each other to bring the surface of the wafer into contact with each other.

2 is a schematic flowchart of a semiconductor device manufacturing process according to an exemplary embodiment. Referring to FIG. 2 , after the polishing pad 210 according to the exemplary embodiment is mounted on the surface plate 220 , a semiconductor substrate 230 is disposed on the polishing pad 210 . In this case, the surface of the semiconductor substrate 230 is in direct contact with the polishing surface of the polishing pad 210 . For polishing, the polishing slurry 250 may be sprayed on the polishing pad through the nozzle 240 . The flow rate of the abrasive slurry 250 supplied through the nozzle 240 may be selected according to the purpose within the range of about 10 cm 3 /min to about 1,000 cm 3 /min, for example, from about 50 cm 3 /min to about It may be 500 ㎤ / min, but is not limited thereto.

Thereafter, the semiconductor substrate 230 and the polishing pad 210 may be rotated relative to each other, so that the surface of the semiconductor substrate 230 may be polished. In this case, the rotation direction of the semiconductor substrate 230 and the rotation direction of the polishing pad 210 may be in the same direction or in opposite directions. The rotation speed of the semiconductor substrate 230 and the polishing pad 210 may be selected depending on the purpose in the range of about 10 rpm to about 500 rpm, for example, may be about 30 rpm to about 200 rpm, It is not limited.

The semiconductor substrate 230 is mounted on the polishing head 260 and is pressed against the polishing surface of the polishing pad 210 by a predetermined load, and then the surface thereof may be polished. The load applied to the polishing surface of the polishing pad 210 on the surface of the semiconductor substrate 230 by the polishing head 260 may be selected according to the purpose in the range of about 1 gf/cm 2 to about 1,000 gf/cm 2 . and may be, for example, about 10 gf/cm 2 to about 800 gf/cm 2 , but is not limited thereto.

In one embodiment, in the method of manufacturing the semiconductor device, in order to maintain the polished surface of the polishing pad 210 in a state suitable for polishing, the semiconductor substrate 230 is polished and the conditioner 270 is used simultaneously with the polishing. The method may further include processing the polishing surface of the pad 210 .

In the polishing pad according to the embodiment, the content of oxygen (O) element in the polishing layer, and the total content of nitrogen (N) and oxygen (O) elements, furthermore, nitrogen (N), oxygen (O) and hydrogen ( H) Since the polishing rate can be improved by controlling the total content of the element, a semiconductor device of excellent quality can be efficiently manufactured using the polishing pad.

[Example]

It will be described in more detail through the following examples, but is not limited to the scope of these examples.

Example

Example 1

(1) Preparation of urethane-based prepolymer

A diisocyanate compound, polytetramethylene glycol (PTMG) as a polymer type polyol, and diethylene glycol (DEG) as a monomolecular type polyol were added to a four-neck flask and reacted at 80 ° C. for 2 hours to prepare a urethane-based prepolymer did. The contents of the diisocyanate compound and the polyol are shown in Table 1.

(2) Manufacture of polishing pad

A casting apparatus equipped with a tank and an input line for supplying raw materials such as a urethane-based prepolymer, a curing agent, and a foaming agent, respectively, was prepared. The previously prepared urethane-based prepolymer, 4,4'-methylenebis(2-chloroaniline) (MOCA, Ishihara Corporation) as a curing agent, and a solid foaming agent (Akzonobel Corporation) were filled in each tank. Through each input line, the raw material was added to the mixing head at a constant speed while stirring. At this time, the prepolymer and the curing agent were added in an equivalent ratio of 1:1.

The stirred raw material was discharged into a mold (1,000 mm x 1,000 mm x 3 mm), but after injection at a discharge rate of 10 kg/min, casting was performed at about 120 ° C. to obtain a molded article. Thereafter, the upper and lower ends of the molded body were cut by a thickness of 0.5 mm, respectively, to obtain an abrasive layer having a thickness of 2 mm.

Thereafter, the polishing layer was subjected to surface milling and groove forming processes, and was laminated with the support layer using a hot melt adhesive to obtain a polishing pad.

Examples 2 to 4

As shown in Table 1 below, a polishing pad was obtained in the same manner as in Example 1, except that the amount of each component was changed.

Comparative Examples 1 to 3

As shown in Table 1 below, a polishing pad was obtained in the same manner as in Example 1, except that the amount of each component was changed.

Specific process conditions of the abrasive layer, and the content of each component are summarized in Table 1 below. The weight% of each component is calculated based on the total weight (100% by weight) of the composition for manufacturing a polishing pad.

Test Example 1: Measurement of element content in abrasive layer

The content of each element and the total content of each element in the polishing layer of the polishing pad obtained in Examples and Comparative Examples were checked using an element analyzer, model name Flash2000 (Thermo Fisher Scientific, Germany). The element content is measured by the top pad of the polishing pad.

The results are summarized in Table 2 below. The weight % values in Table 2 below are weight % values based on the total weight of the abrasive layer.

As can be seen from Table 2, the polishing pads prepared in Examples 1 to 4 had an oxygen (O) element content in a range of 15 wt% to 19 wt% in the polishing layer, and nitrogen (N) and oxygen ( O) It was confirmed that the total content of the element was within the range of 20 wt% to 27 wt%.

On the other hand, in the polishing pad prepared in Comparative Example 1, the content of oxygen (O) element in the polishing layer exceeded the 19 weight range, and the polishing pad prepared in Comparative Example 2 had the oxygen (O) element content in the polishing layer. It was less than 15 weight range, and it was confirmed that the total content of nitrogen (N) and oxygen (O) elements in the polishing pad prepared in Comparative Example 3 was less than 20 weight %.

Experimental Example 2: Physical properties of polishing pad

With respect to the physical properties of the polishing pads prepared in Examples and Comparative Examples, the following items were tested, and the results are shown in Table 3 below.

(1) specific gravity

The polishing pad prepared according to the above Examples and Comparative Examples was cut into a rectangle (thickness: 2 mm) of 4 cm Х 8.5 cm, and then left at a temperature of 23±2° C. and a humidity of 50±5% for 16 hours. The specific gravity of the polishing pad was measured using an HPE ?D hydrometer.

(2) pore properties

Cross-sections of the polishing pads of Examples and Comparative Examples were observed with a scanning electron microscope (SEM).

In addition, the characteristics of the pores were calculated based on the SEM image and summarized in Table 3 below.

- Number average diameter: the average of the sum of the pore diameters on the SEM image divided by the number of pores

- Number of pores: the number of pores per ^{0.3 cm 3 on the SEM image}

- Pore area ratio: Percentage of the area of pores only compared to the total area of the SEM image

As can be seen from Table 3, it was confirmed that the polishing pads prepared in Examples 1 to 4 had a number average diameter of 20 to 26 μm, and a pore area ratio of 41% to 45%.

(3) removal rate

The initial polishing rate immediately after the polishing pad was manufactured was measured as follows.

Silicon oxide was deposited on a silicon semiconductor substrate having a diameter of 300 mm by a chemical vapor deposition (CVD) process. A polishing pad was attached to the CMP equipment, and the silicon oxide layer of the silicon semiconductor substrate was installed to face the polishing surface of the polishing pad. Thereafter, the polishing load was adjusted to be 4.0 psi and the silicon oxide film was polished by rotating the platen at 150 rpm for 60 seconds while injecting the calcined ceria slurry onto the polishing pad at a rate of 250 ml/min while rotating the polishing pad at 150 rpm. . After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, washed with purified water (DIW), and dried with nitrogen (N) for 15 seconds. The thickness of the dried silicon wafer was measured before and after polishing using an optical interference thickness measuring device (manufacturer: Kyence, model name: SI-F80R). Then, the polishing rate was calculated using Equation 1 below.

[Equation 1]

Polishing rate (Å/min) = Polishing thickness of silicon wafer (Å)) / Polishing time (min)

As shown in Table 4 and FIG. 1, in the polishing pads of Examples 1 to 4, the content of oxygen (O) element in the polishing layer, and the total content of nitrogen (N) and oxygen (O) elements were within the scope of the present invention. It was confirmed that the polishing rate for oxide was about 3628 Å/min and 3910 Å/min, and the number of scratches was also significantly reduced compared to Comparative Examples 1 to 3 with 1 to 3 scratches.

On the other hand, in the case of the polishing pad of Comparative Example 1, the polishing rate for oxide was about 2809 Å/min, and it was confirmed that the polishing pad of Examples 1 to 4 was significantly reduced by 20% or more. This is because the content of element oxygen (O) is 19.2% by weight based on the total weight of the polishing pad, which is too large, so that _{the bonding strength between the abrasive particles used during polishing, ceria (CeO 2} ) particles and the polishing pad is excessively increased, so ceria ( CeO ₂ ) It is thought that the removal rate was adversely affected because the bonding force between the particles and the wafer was rather reduced.

In addition, in the case of the polishing pads of Comparative Examples 2 and 3, the polishing rate was excessively increased to 4108 Å/min or more, and the number of scratches was also significantly increased compared to Examples 1 to 4 to 15 or more. It is considered that the content of element oxygen (O) or the total content of elements nitrogen (N) and oxygen (O) is outside the scope of the present invention, and thus the polishing rate and scratches are adversely affected.

210: polishing pad 220: surface plate
230: semiconductor substrate 240: nozzle
250: polishing slurry 260: polishing head
270: conditioner

Claims (18)

An abrasive layer comprising a cured product of a composition comprising a urethane-based prepolymer, a curing agent and a foaming agent,
The content of oxygen (O) element in the abrasive layer is 15 wt% to 19 wt% based on the total weight of the abrasive layer,
The total content of nitrogen (N) and oxygen (O) elements in the abrasive layer is 20 wt% to 27 wt% based on the total weight of the abrasive layer,
The polishing layer includes a plurality of micropores, polishing pad.
The method of claim 1,
The polishing pad, wherein the content of oxygen (O) element in the polishing layer is 16 wt% to 18.9 wt% based on the total weight of the polishing layer.
The method of claim 1,
The total content of carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) elements in the polishing layer is 92 wt% to 96 wt% based on the total weight of the polishing layer, the polishing pad.
4. The method of claim 3,
The total content of nitrogen (N), oxygen (O) and hydrogen (H) elements in the polishing layer is based on the total content of carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) elements. 30% to 35% by weight of the polishing pad.
5. The method of claim 4,
The total content of elements other than carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) is 4 wt% to 8 wt% based on the total weight of the polishing layer, the polishing pad.
The method of claim 1,
The polishing pad, wherein the urethane-based prepolymer comprises a prepolymerization product of at least one diisocyanate compound and at least two polyols.
7. The method of claim 6,
The oxygen (O) element in the polishing layer is derived from the diisocyanate compound and the polyol,
The molar ratio of the oxygen (O) element derived from the polyol and the oxygen (O) element derived from the diisocyanate compound is 1:0.1 to 0.5, the polishing pad.
7. The method of claim 6,
The at least two polyols are at least one monomolecular polyol and at least one polymer polyol,
The polishing pad may have a mixing weight ratio of the diisocyanate compound and the polyol of 1: 1.35 to 1.55;
A mixing weight ratio of the monomolecular polyol and the high molecular polyol 1: 8 to 10;
A mixing weight ratio of the diisocyanate compound and the polymer-type polyol 1: 1.2 to 1.43; and
The diisocyanate compound and the mixing weight ratio of the monomolecular polyol 1: 0.11 to 0.15; satisfying at least one of the mixing weight ratio of the polishing pad.
7. The method of claim 6,
The content of the diisocyanate compound is 29.9 wt% to 35 wt% based on the total weight of the composition, the polishing pad.
9. The method of claim 8,
The content of the polymer-type polyol is 35 wt% to 42.8 wt% based on the total weight of the composition, the polishing pad.
9. The method of claim 8,
The content of the monomolecular polyol is 4.0 wt% to 4.5 wt% based on the total weight of the composition, the polishing pad.
The method of claim 1,
The content of the curing agent is 16.0 wt% to 20 wt% based on the total weight of the composition, the polishing pad.
9. The method of claim 8,
The polymeric polyol is polytetramethylene glycol (PTMG), polytetramethylene etherglycol (PTMEG), polyether polyol, polyester polyol, polycarbonate polyol ) and polycaprolactone polyol (polycarprolactone polyol) comprising at least one selected from the group consisting of, a polishing pad.
9. The method of claim 8,
The monomolecular polyol comprises at least one selected from the group consisting of ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), propanediol (PDO) and methylpropanediol (MP-diol) , polishing pad.
The method of claim 1,
The curing agent is 4,4'-methylenebis (2-chloroaniline) (4,4'-methylenebis (2-chloroaniline); MOCA), diethyltoluenediamine (DETDA), diaminodiphenylmethane (diaminodiphenylmethane) , diaminodiphenylsulfone, m-xylylenediamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, Contains at least one selected from the group consisting of polypropylenediamine, polypropylenetriamine, and bis(4-amino-3-chlorophenyl)methane which is a polishing pad.
The method of claim 1,
wherein the polishing pad has a removal rate for oxide of 3000 Å/min to 4000 Å/min.
preparing a composition by sequentially or simultaneously mixing a urethane-based prepolymer, a curing agent, and a foaming agent; and
Including; injecting the composition into a mold and curing it to form an abrasive layer;
The content of oxygen (O) element in the abrasive layer is 15 wt% to 19 wt% based on the total weight of the abrasive layer,
The total content of nitrogen (N) and oxygen (O) in the abrasive layer is 20 wt% to 27 wt% based on the total weight of the abrasive layer,
The polishing layer comprises a plurality of micropores, a method of manufacturing a polishing pad.
Polishing the surface of the semiconductor substrate using a polishing pad,
The polishing pad includes a polishing layer comprising a cured product of a composition including a urethane-based prepolymer, a curing agent and a foaming agent,
The content of oxygen (O) element in the abrasive layer is 15 wt% to 19 wt% based on the total weight of the abrasive layer,
The total content of nitrogen (N) and oxygen (O) in the abrasive layer is 20 wt% to 27 wt% based on the total weight of the abrasive layer,
The polishing layer comprises a plurality of micropores, a method of manufacturing a semiconductor device.

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